Telephone system



Nov. 10, 1931. A. E. HAGUE TELEPHONE SYSTEM Filed April 19, i950 wmvrop A. E. HAGUE i III D'I ATTORNEY 'ALFRED'E-HAGUE, OF WEST ORANGE, NEW JERSEY, 'ASSIG'NOR Patented Nov. 10, 1931 "UNITED STATES PATENT OFFICE LABORA'IORIES, "INCORPORATED, OF YORK TO'IBELL rnnnrnonn TELEPHONE SYSTEM Application filed April -19,

This invention: relates to telephone systems and-particularly tothe identification of calling stations on party lines. o

The objectsiof the invention are to secure apositivevand reliabletest of party lines to identify. the calling party, to simplify the equipment usedfor'this-purpose, to effect an economy thereimand'to otherwise improve systems of this character.

According to thisinvention, all of thestations of a tfour party line are equipped with unidirectional devices which are connected in series withlthesignal bellwindings to ground such that-a test current of onepolarity will, when applied" to the line, flow through the bell windings at two stations, while current of opposite-polarity=Will fiowthrough the bell windings at the other two stations. In addition, two .Of the stationsare arranged to close, when calling, an unobstructed path across thetip and ring conductors of the line, whereas the other two "stations when calling close bridgesthrough other unidirectional current controllingdevices'in such 'a manner that, if a test is made overlthe line as a loop, current willfiow if-lthe calling stationisone of the first mentioned pair but will not flow if it is one of thesecond pair.

VA feature ofthe invention is a circuit arrangement by which'the directional devices, whichcontrol the 'fiow of-test currentthrough the bell windings, are shunted when the receiverison the switchhook so that ringing current can flow frornthe line-directly to the bells and not be required topass-through said devices; The removal of the receiver opens theshunt-and includes the'bell winding and thedirectional current controlling device in a circuit -.to the line conductors for the identifying test.

' An advantage oftliis arrangementis that both loop and ground return circuits may be used to test *for the calling station. -A further advantage isthat by'using the grounded bell winding asia -part of-the test circuit the impedance'ofgthis winding serves to prevent interference with :the transmission characteristics of t-he line during conversation, thus obviatinglthel necessity of pro'viding a retardation coil ifori-thatipur posei included in 1930. Serial No. 445,553.

vices 31 and 35are connectedvbetween the;

line and the respective substation bell windings 32 and 36 in such away that'currentof negative polarity is permitted to flow from the line through the windings of these bells to vground. At stations, C andD, the devices 38 and-42 are connected in series with the bells 39 and 43 respectively in sucha manner that current of positive polarity is permitted to'fiow from the line to ,ground. At stationsiB and D,-the devices 34 and tlh are connections leading from the tip side of the line through one winding of the repeating coil, a switchhook contact, the talking transmitter and theimpulsesender to the opposite sideofthe line. These devices are so connected as-to resist flow of negative current when applied to the-ti-p side'of the-line. The unidirectional current devices may b'e'of any suitable type such as described in the Journal of the American Institute of Electrical Engineers for March 1927, page 215. v

The line L extends toithe central ofiice and terminates in the contact bank of a line'finder switch F, which is illustrated schematically by the brushes 58 to 63 inclusive. The line finderF extends the line tothe brushes of the selector switch S, also shown-schematically. The finder F and selector S may be ofany suitable type such as the power-drivenpanel type switches described in the Quarrie No. 1,177,044, granted March 28, 1916, andinthe patentto Craft etal. No. 1,- 123,696, granted -January5, 1915. The selector S, and succeeding selector switches may be controlled by central oifice register patent to Mc- 7 new YORK, 'N. Y., A CORPORATION 'oFNEw senders such as described in detail in the ing negative current patent to Kopp No. 1,589,402, granted June 22, 1926 and in the patent to Stearn et al No. 1,395,977, granted November 1, 1921.

Since each vi ded with an individual message register at the central office, registers 81 to 84 inclusive, it is necessary to make a test of the line at some convenient time to determine which substation has initiated the call. The testing equipment at the central office comprises two relays 67 and 68 and oppositely poled sources of current 85 and 86 together with relay 71 and the source of potential 88. The test is divided into two parts, the first or preliminary test serving to determine which pair of stations is responsible for the call. The second or final test is made by the relay 71 and serves in combination with the first test to identify the particular station that has initiated the call. The first test consists in applying first negative current from the source 85 and then positive current from the source 86 to the two sides of the line in simplex, and the second part of the test consists in applyfrom the source 88 to the tip side of the line and ground potential to the ring side of the line.

Taking up the detailed description, it will first be assumed that a call is originated at the'substation A. The initiation of the call sets the line finder F in operation to find the calling line. Followingthis, the called line designation is sent by the impulse transmitter 44 and recorded at the central ofiice for the purpose of operating the switch S and succeeding switches to complete the extension of the connection to the called line. At some convenient point in the extension of the connection the controlling sequence switch 70, associated with the selector switch S and finder F, reaches some position such as position 12. As soon after the sequence swltch reaches position 12 as the power driven interrupter 69 closes its upper contact, a circuit is completed from ground through said contact of the interrupter, sequence switch spring 7 3, left back contact of relay 66, lower winding of relay 64 to battery. Relay 64 operates and locks through its upper winding and contact to ground at the contact of spring 74. WVith relay 64 actuated, the tip and ring conductors of the line L are extended through the brushes 58 and 59, front contacts of relay 64, back contacts of relay 65, conductor 87, outer right back contact of relay 66, left winding of test relay 67 to the of the four substations is proextends through the right winding of the induction coil, switchhook contacts, receiver 48 and the left winding of the induction coil to the device 81. Since the negative pole of the source 85 is connected to the test circuit, current will flow through the device 31 to the windings of the bell'32. Accordingly the relay 67 operates and locks through its right winding and contact to ground atspring 77.

'When the interrupter 69 shifts its contacts, a circuit is completed from ground through the lower contacts of said'interrupter, inner lower armature and contact of relay 64, inner lower armature and back contact of relay 65, left winding of relay 66 to battery. Relay 66 operates and locks through its right'winding and contact to the sequence switch spring 74. Relay 66 disconnects the test conductor 87 from the relay 67 and connects it through the left winding of relay 68 to the positive pole of source 86. Due to the polarity of the device 31, current does not flow over the test circuit through the windings of the bell 32 to ground and the relay 68 does not operate.

On the next-shift of the interrupter 69, a circuit is closed from ground through the upper contacts of the interrupter, spring 73',

left armature and front contact of relay 66,

outer left armature and back contact of relay 68, lower winding of relay 65 to battery. Relay 65 operates and locks through its upper winding and contact to ground at sequence switch spring 74. Relay 65 disconnects the test conductor 87 from the line and closes a loop circuit for performing the sec ond part of the test. The operation of relay 68, as a result of the first part of the test, determines that the calling station is either the station A or the station B. The second part or" the test, next to be performed, will determine which one of these two stations has initiated the call. The loop circuit for the second test may be traced from the negative pole of battery 88 through the lower windlng of relay 71, front contacts and uppermost armatures of relays 65and 64, brush 58, thence over the tip conductor 45 through the transmitters 44 and 47at the station A. switchhook contacts, right winding of the induction coil and returning over the ring conductor 46, brush 59, lowermost arma: tures and front contacts of relays 64 and 65 to ground. Relay 71 operates inthis circuit and looks through its upper winding and contact to ground at the sequence switch spring 77.

Later when the interrupter 69 shifts its contacts, a circuit is completed from ground through the lower contacts of said interrupter, inner lower armatures of relays 64 and'65, sequence switch "spring 75, through the winding of the sequence switch magnet 7 O to battery. Thus the sequence switch advances into some subsequent-position indimun thatth'e test has been completed. As the sequence -.switcl1 moves out of position 12 the lioldingcircuits' ofrelays 64, .65, and .66 are opened,and=these relays release. If the call istsuccessful and thecalled subscriber answers, a supervisory relay suchas :thegrelay 79 operates and completes a circuit from ground through sequence switch spring 80, contact of relay 7 9,=right winding of relay 72 to battery. Relay 72 operates and looks through its left winding and contact to ground through the spring 77; Subsequently when conversation is completed and release is taking place, the sequenceswitch 70inoves through successive positions such as POSil3l0I1S'15 to 17. While the sequence switch is moving through these positions, a circuitis completed for operating the register 81 individual to thecalling station'A. This circuit may be traced from battery 'throughthe resistance 78, outer contact of relay 72, sequence switch spring 76', outer right armature and front contact of relay 67, inner left armature and contact of relay v68, middle armature and front contact of relay 71, brush 63 =to the Winding of the register '81 to ground. The register 81 operates and charges the call against the substation A.

As thesequence switch 70 leaves position [7 the test relays 67 and 71 are released. The release-of the'finder switch F and selector switch S take place in the well-known manner. I

If the callis initiated at the substation B instead of substation A, therelay 67 operates in the first part ofthe test the samev as it did in the case above described; On the second partef the test, however, the relay 71 does not operate since'current of negative polarity cannot flow from the tip conductor through the device 34 to the ring conductor 46. "The refore the metering circuit may now be traced from battery resistance 78, contact ofvrelay' 72, spring 76, outer right armature and front contact of relay 67, innermost armature of relay 68, middle armature and back contact of relay 71, brush 62, winding of register 82 to ground.

Assume next that the call is initiated at the substation C. lVhen the negative pole of source 85 is connected to'the line, current will "not flow .since the device88 is arranged to permit flow of positive current only. Ac- *cordingly the relay '67 does not operate. Later, "how'eventhe'relay 68 is operated due to the flow of current from the positive source 86 through the device 38 andithe winding of the'bell 39 to ground." During the sec- Iontl part-of the test, relay 71 isoperated since {there is no obstructionl to the flow ofcurren't from the tip conductor 45m the ring contluctor at the substation Under these conditions, the {metering circuit may be traci-id ffrom battery through the resistance '78, contact'of relay72, spring76, outer armathe signal device t on, and means ture and back-contact of relay v67,,middle armature and. front contact of relay; :68, up,-

permost armature and front. contact of relay '71, brush .61 to the wind-ingot the register 83, which is individual to the substation TC.

Assume finally that a call is originated at the substation D. In this casethe relay 6?? remains inert, and the relay J 68; operates the T-herefore the metering ture and back contact of relay 7'1, brush to the Winding of the register 84indiv-idual to the substation ZD. v i 1 It will be noted that the devices 31, 35, 38,

relay 71 does not operate be traced from battery through 4.2, individual to the respective substations A, B, C, and D,-are normallyshunted by the respective switchhook springs 30, .33, -37, and 4-0 whilethe receivers are on the hooks. This permits ringing current to flow from the line conductors directly -to the ringers 32, 36,39, and 13 without having to traverse i the unilateral devices.

The devices 31, 35, :88, .and 42 may offer only slight impedance to theflow of voice currents, but the transmissiol'i characteristics of the line are unimpaired owing to the high impedance of the windings by the sub station bells. Thus: the ground connections of the substation ringers are employed "for testing purposes Without interfering with the talking characteristics of the line and withcut thenecessity of supplying an additional impedance for this purpose such as a choke coil. w

' While the invention has been illustrated in connect1on with systems of a certain type, it'will be understood that'it is not so'limited but is applicable to various types of systems.

'What is claimed is:

1. In a telephone system, :a line having a plurality of stations thereon, signal devices, oneat e-ach station,'individual test circuits for said stations, each test circuit including atthe corresponding staresponsive to the flow of. current insaid circuits one station'from another.

2.:Inja telephone system, a line having a plurality of stations thereon, signal bells having actuating windings, one bell at each of said I said stations,.each test circuitincluding the and means responsive to the flowof current for discriminating stations, individual test circuits for winding 'of the corresponding signal bell,

direction of current 3. The combination in a telephone system of a line having a number of stations thereon, signal devices, one at each station, a source of potential, individual test circuits for said stations for connecting said lineto said source, each test circuit including the signal ing device at the corresponding station, and means responsive to the flow of current in said test circuits to enable a test for discriminatin g between said stations.

4;. In a telephone system, a line having a plurality of stations thereon, call bells, one for each station, individual circuits for said stations, each circuit including the call bell at the corresponding station, a source of current, and means for controlling the direction of flow of current in said circuits to identify one station from another.

5. In a telephone system, a party line, signal bells having windings which oil'er a high impedance to talking currents, each station on the line being provided with one of said bells, individual test circuits for said stations, each circuit including the winding of the corresponding bell, and testing means controlled in accordance withthe flow of current in said test'circuits for identifying said stations.

6. In a tclepho'nesystem, a line having a plurality of stations thereon, individual signal devices for said stations, individual test circuits for said stations,each test circuit including the corresponding signal device, cur-. rent cont-rolling devices, one in each of said circuits for controlling the flow of current therein, and 11163618 effective according to the flow of current in said circuits for identity ing one of said stations.

.7. The combination in a telephone system of a line having a number of stations thereon, individual signal devices for said stations,

individual test circuits for said stations, each test circuit including the corresponding signal device, directional current controlling devices, one in each of said circuits for controlling the direction of current flow therein, and means effective according to the direction of flow of current in said circuits for identitying, one of said stations.

8. In a telephone system, a line having a plurality of stations, individual signal bells for said stations, individual test circuits for said stations, each circuit includii g the cor responding signal bell, directional devices, one in each of said circuits, certain of said devices permitting theflow of current in one direction and other of said devices permitting the rection, and means eiiective according to the flow in said circuits for identifying said stations. V V

9. In a telephone system, a line having two substations thereomisignal bells,.one for each station, individual test circuits for said stations, each circuit including the correspondflow of current in the opposite diing signal bell, a current controlling device in one of said circuits for permitting current of positive polarity to flow therein, another current controlling device in the other circuit for permitting the flow of current of negative polarity, and means dependent upon the direction of current flow for identifying one of said stations.

10; In a telephone system, a line having a plurality. of stations, individual signal bells for said stations, means at each station for closing a bridge across the sides of said line, a test circuit including the sides of said line in series, means in certain of said bridges to prevent the flow of current in said test circuit, other test circuits, including said signal bells, andmeans controlled by said test circuits tor-identifying one of said stations.

11. In a telephone system, a line having a number of stations thereon, individual signal bells for said stations, a test circuit including'both sides of the line in parallel and said signal bells, means at each station for closing a bridge across the sides of said line, another circuit including the sides of said line in series, in cans in certain of said bridges to prevent flow of current in said second-mentioned test circuit, and means controlled by said test circuits for identifying one of said stations. y Y

12; In a telephone system, a line having a number of stations thereon, individual signal bells for said stations, a test circuit including one of said bells, a second test circuit including another ofsaid bells, a third test circuit excluding all of said bells, and means controlled by said test circuits for identifying one of said stations 13. In a telephone system, a line having a number of stations thereon, individual bells for said stations, a first test circuit including one of said bells, a directional device in said test circuit for permitting the flow of current otone polarity, a second test circuit including another of said bells, a directional device in said second circuit for permitting the flow of current of opposite polarity, and means controlled by said test circuits for identifying one of said stations. r

14:. In a telephone system, a line having a substation thereon, a signal bell at said substation connected'to said line, a unidirectional device in circuit with said bell for admiting current of a given polarity, and means for closing a shunt around said device.

=15. In a telephone system, a line having a substation thereon, asignal bell at said substation connected to said line, sources of test current of difi'erent polarity, a current controlling device in circuit with said bell for permitting the flow of test current of a given polarity, source of ringing current, and means for causing rlngmg current to flow .to said bell without traversing said device.

H 16. Ina telephone system, a-line having a inl 

